Noninvasive detection of a physiologic parameter within a body tissue of a patient

Abstract

The invention provides a device for contacting a surface of a tissue within a patient's body to determine a physiologic parameter of the patient. The device typically comprises a sensor responsive to the physiologic parameter and a probe housing the sensor. The probe is constructed to allow the sensor to be secured at a sensing area adjacent to a surface of a patient's tissue, without need for an adhesive and without disturbing the blood flow within the measurement region of the tissue. The device may also include a means for reducing interference in the sensing area. Preferably, the device further comprises an indicating means operably connected to the sensor for indicating an analyte quantity and/or concentration associated with the physiologic parameter. The invention also provides a method for determining a physiologic parameter of a patient.

We claim: 
     
       1. A device for preventing the application of excessive pressure to a measurement region in tissue comprising:
 a probe body having distal and proximal ends, said distal end including a top non-permeable covered portion and a bottom portion defined by a perimeter surface, said perimeter surface defining a recess within said bottom portion; 
 a single sensor responsive to a quantity of analyte to be measured, the sensor being unobstructedly positioned within the recess wherein the sensor is responsive to analyte concentration through a chemical reaction with a reactant; 
 wherein in use said top non-permeable covered portion and said perimeter surface create a covered, isolated measurement area within said recess, said recess containing said analyte, which is thereby prevented from dissipating from the measurement area and further wherein the configuration of the perimeter surface and the position of the sensor within the recess allows said analyte measurement to be free of pressure artifact. 
 
     
     
       2. The device of  claim 1 , wherein the bottom portion perimeter and recess are adapted to reduce interference from electromagnetic radiation. 
     
     
       3. The device of  claim 1 , wherein the bottom portion perimeter and recess are adapted to reduce interference from a fluid. 
     
     
       4. The device of  claim 3 , wherein the fluid is a gas. 
     
     
       5. The device of  claim 3 , wherein the fluid is a liquid. 
     
     
       6. The device of  claim 3 , wherein the bottom portion perimeter and recess for preventing analyte from dissipating from the measurement area allows the analyte to come into equilibrium within the measurement area. 
     
     
       7. The device of  claim 6 , wherein the probe body is sized to fit a nares, mouth, or cheek. 
     
     
       8. The device of  claim 1 , wherein the physiologic parameter is a quantity of an analyte. 
     
     
       9. The device of  claim 8  wherein the analyte is selected from the group consisting of tissue pH, temperature, CO 2 , pCO 2 , O 2 , glucose, pyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, ADP, ATP, succinate, fumarate, malate oxaloacetate, NAD, NADH, and combinations thereof. 
     
     
       10. The device of  claim 1 , wherein the physiologic parameter is the concentration of an analyte. 
     
     
       11. The device of  claim 10 , wherein the analyte is selected from the group consisting of tissue pH, temperature, CO 2 , pCO 2 , O 2 , glucose, pyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, ADP, ATP, succinate, fumarate, malate oxaloacetate, NAD, NADH, and combinations thereof. 
     
     
       12. The device of  claim 10 , further comprising an indicating means operably connected to the sensor for indicating analyte concentration in the patient. 
     
     
       13. The device of  claim 1 , wherein the device further comprises a holding means for immovably securing the device in position. 
     
     
       14. The device of  claim 13 , wherein the holding means comprises a clip. 
     
     
       15. The device of  claim 13 , wherein the holding means comprises a handle. 
     
     
       16. The device of  claim 13 , wherein the holding means is adapted to immovably secure the device without applying a pressure greater than about 1.5×10 4  pascals. 
     
     
       17. The device of  claim 1 , wherein the sensor is responsive to a gas. 
     
     
       18. The device of  claim 17 , wherein the gas is selected from oxygen, carbon dioxide, nitrous oxide, desflurane, enflurane, halothane, isoflurane, methoxyflurane, and sevoflurane. 
     
     
       19. The device of  claim 1 , wherein the sensor is responsive to pH. 
     
     
       20. The device of  claim 1 , wherein the sensor is responsive to blood flow. 
     
     
       21. The device of  claim 1 , wherein the sensor is responsive to an analyte selected from the group consisting of tissue pH, temperature, CO 2 , pCO 2 , O 2 , glucose, pyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, ADP, ATP, succinate, fumarate, malate oxaloacetate, NAD, NADH, and combinations thereof. 
     
     
       22. The device of  claim 1 , further comprising at least one additional sensor. 
     
     
       23. The device of  claim 22 , wherein the device is adapted for multiple use. 
     
     
       24. The device of  claim 23 , wherein the sheath has a selectively permeable portion that allows transmission of the analyte therethrough. 
     
     
       25. The device of  claim 24 , wherein the selectively permeable portion comprises a silicone. 
     
     
       26. The device of  claim 24 , wherein the selectively permeable portion comprises a porous membrane. 
     
     
       27. The device of  claim 1 , wherein the device further comprises a temperature detecting means for detecting temperature at the sensor. 
     
     
       28. The device of  claim 27 , wherein the temperature detecting means is detachable with respect to the device. 
     
     
       29. The device of  claim 1 , further comprising a sheath covering the probe body. 
     
     
       30. The device of  claim 29 , wherein the device is adapted for single use. 
     
     
       31. The device of  claim 30 , wherein the sheath has a selectively permeable portion that allows transmission of the analyte therethrough. 
     
     
       32. The device of  claim 31 , wherein the selectively permeable portion comprises a silicone. 
     
     
       33. The device of  claim 31 , wherein the selectively permeable portion comprises a porous membrane. 
     
     
       34. The device of  claim 29 , wherein the sheath comprises a rigid portion. 
     
     
       35. The device of  claim 29 , wherein the sheath is disposable. 
     
     
       36. The device of  claim 35 , wherein the sheath comprises a rigid portion. 
     
     
       37. The device of  claim 35 , wherein the sheath is disposable. 
     
     
       38. The probe of  claim 1  wherein at least a portion of said probe body comprises a material that allows said portion to deform in response to force applied to the device. 
     
     
       39. The device of  claim 38 , wherein the material comprises a polymer. 
     
     
       40. The device of  claim 39 , wherein the polymer is selected from the group consisting of polyethylene, polypropylene, polybutylene, polyamide, polyimide, polyester, perfluorinated polymer, polystyrene, poly (vinyl chloride) and elastomers. 
     
     
       41. The device of  claim 1 , wherein the sensor is a Severinghaus-type sensor. 
     
     
       42. The device of  claim 1 , wherein the analyte concentration is the concentration of an analyte selected from the group consisting of tissue pH, temperature, CO 2 , pCO 2 , O 2 , glucose, pyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, ADP, ATP, succinate, fumarate, malate oxaloacetate, NAD, NADH, and combinations thereof. 
     
     
       43. The device of  claim 1 , wherein the sensor is constructed to be responsive to analyte concentration through absorption, emission or modification of electromagnetic radiation. 
     
     
       44. The device of  claim 43 , wherein the analyte concentration is the concentration of an analyte selected from the group consisting of tissue pH, temperature, CO 2 , pCO 2 , O 2 , glucose, pyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, ADP, ATP, succinate, fumarate, malate oxaloacetate, NAD, NADH, and combinations thereof. 
     
     
       45. The device of either  claim 44 , wherein the radiation is ultraviolet, visible, near infrared, or far infrared. 
     
     
       46. The device of either  claim 43 , wherein the radiation is ultraviolet, visible, near infrared, or far infrared. 
     
     
       47. The device of  claim 1 , wherein the sensor is responsive to analyte concentration through generation or alteration of an electrical current. 
     
     
       48. The device of  claim 47 , wherein the analyte concentration is the concentration of an analyte selected from the group consisting of tissue pH, temperature, CO 2 , pCO 2 , O 2 , glucose, pyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, ADP, ATP, succinate, fumarate, malate oxaloacetate, NAD, NADH, and combinations thereof. 
     
     
       49. The device of  claim 1  wherein said probe body is constructed to allow the sensor to be secured in the measurement region without relying solely on an adhesive. 
     
     
       50. The device of  claim 49 , wherein the sensor is detachable with respect to the probe. 
     
     
       51. The device of  claim 50 , wherein the sensor contains a chemical that changes color in the presence of an analyte associated with the physiologic parameter. 
     
     
       52. The device of  claim 1 , wherein the analyte is selected from the group consisting of tissue pH, temperature, CO 2 , pCO 2 , O 2 , glucose, pyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, ADP, ATP, succinate, fumarate, malate oxaloacetate, NAD, NADH, and combinations thereof. 
     
     
       53. The device of  claim 1  further comprising a clip member coupled to the probe body for immobilizing the device, the clip member having a first portion that extends generally perpendicular from the probe body and a second portion that is generally parallel to the probe body. 
     
     
       54. The device of  claim 53 , wherein the clip member further comprises a spring mechanism disposed between the first and second portions for preventing application of excessive pressure to the measurement region. 
     
     
       55. The device of  claim 53 , wherein the second portion of the clip member includes one or more pleats for preventing application of excessive pressure to the measurement region. 
     
     
       56. The device of  claim 53 , wherein the second portion includes a perforated section for preventing application of excessive pressure to the measurement region. 
     
     
       57. The device of  claim 53 , wherein the second portion includes an elastically deformable region for preventing application of excessive pressure to the measurement region. 
     
     
       58. The device of  claim 1  further comprising a pad positioned on the perimeter of the bottom portion. 
     
     
       59. The device of  claim 58 , wherein the at least one pad member is formed from a compliant material. 
     
     
       60. The device of  claim 59 , wherein the compliant material comprises foam. 
     
     
       61. The device of  claim 59 , wherein the compliant material comprises rubber. 
     
     
       62. A device for preventing the application of excessive pressure to a measurement region in tissue comprising:
 a probe body having distal and proximal ends, said distal end including a top non-permeable covered portion and a bottom portion defined by a perimeter surface, said perimeter surface defining a recess within said bottom portion; 
 a single sensor responsive to a physiologic parameter to be measured, the sensor being unobstructedly positioned within the recess so as not to contact said tissue surface; 
 wherein in use said top non-permeable covered portion, said perimeter and said recess create a covered, isolated measurement area containing an analyte thereby prevented from dissipating from the measurement area and further wherein a resulting analyte measurement is free of pressure artifact and further wherein the sensor is responsive to analyte concentration through a chemical reaction with a reactant. 
 
     
     
       63. A device for preventing the application of excessive pressure to a measurement region in tissue comprising:
 a probe body having distal and proximal ends, said distal end including a top non-permeable covered portion and a bottom portion defined by a perimeter surface, said perimeter surface defining a recess within said bottom portion; 
 a single sensor responsive to a physiologic parameter to be measured, the sensor being unobstructedly positioned within the recess; and 
 a clip member coupled to the probe body for immobilizing the device with respect to the tissue, the clip member having a first portion that extends generally perpendicular from the probe and a second portion that is generally parallel to the probe, 
 wherein in use said tissue surface said top non-permeable covered portion, said perimeter and said recess create a covered, isolated measurement area containing an analyte thereby prevented from dissipating from the measurement area and further wherein the configuration of the perimeter surface and the position of the sensor within the recess allows said analyte measurement to be free of pressure artifact.